Grand Prix "Runs away"
My 2002 Grand Prix GTP has 185000km on it and has been great to me except for this one(major) issue that started not too long ago. The car, at times, will just rev up on its own for no apparent reason to anywhere from 2000-4500 rpm and just sticks there for some time or untill the car is shut off. If it is shut off in the middle of one of its fits, it will not start unless the gas peddle is held to the floor, and when it does start it blows smoke and sounds like its only running on 3 cylinders and it resumes running away once its firing on all 6 again. It will run away when its hot, cold, at speed, stoped and completely at random. I have looked for a cause to its running away and replaced the MAF, IAC and TPS with brand new ones and it still does this. Have disconected the cruise control because I have heard that that maybe be a cause and it still runs away even after doing so. Only way I have found to stop it running away is to just wait for it to stop which usualy takes a few minutes(5-6) of it just sitting in park or floor it through first gear and let it shift once and that will usualy bring it back down to what it normaly should be at and it will carry on like nothing happened untill it acts up again. Pretty sure it is not a vacum leak because it does stop and its not constant. I am a bit loss with this issue and can't think of what else may be causeing it. Any ideas?